The Acute Phase Protein Profile in Inflammatory Arthropathies

Abstract

A quantitative evaluation of the changes of the levels of acute phase reactants (APRs) during inflammatory phenomena is a useful tool both in monitoring the course of some inflammatory diseases and the efficacy of the anti-inflammatory therapy. Nonetheless, the information collected through the various indices appears unable to provide either an overall digital evaluation of the phenomenon or an easy correlation with the clinical state findings. In fact, APRs appear to have different sensitivities in detecting an inflammatory state: some proteins rise immediately to high or very high levels when an inflammatory process flares up and their plasma concentrations are strictly related to the inflammation activity, whilst some others have longer latency times and less sensitivity to small variations in the inflammatory condition. Moreover, the normal inflammatory response is characterised by the almost simultaneous increase of many proteins. A good laboratory evaluation of this condition must take into proper account the overall changes of different indices with their relative range of variation.

An adequate statistical approach to the problem can give the clinician a reliable method of assessing the inflammatory phenomenon, with a single inflammatory activity index (IAI). This index is an overall measure of the inflammation state, with which the levels of APRs are related; its usefulness can be found particularly during short-term trials on the efficacy of non-steroidal anti-inflammatory drugs (NSAIDs) in chronic inflammatory diseases, when the most common and simple tests fail because of their latency times.